Shaft positioning apparatus



Feb. 10, 1953 "R. w. MAY 2,627,957

SHAFT POSITIONING APPARATUS Filed June 20, 1950 4 Sheets-Sheet llllllllllIlllll'll-lllllllllllllll H -Hlll Inveazow:

Feb. 10, 1953 y R. W. MAY 2,627,957

SHAFT PosITIoNING APPARATUS Feb. 10, 1953 R. W. MAY 2,627,957

SHAFT POSITIONING APPARATUS Filed June 20, 1950 4 Sheets-Sheet 5 42 36)MN l 4@ 74%@ ,A 40,

| 47 l a J2 2 :I- 32 .v-.. 35 4a /f 4?/ a 54 4s 4 36 34 l 4844 a i /8 Qf` il Feb. l0, 1953 R. w. MAY 2,627,957

SHAFT POSITIONING APPARATUS Filed June 20, 1950 4 Sheets-Sheet 4Patented Feb. 10, 1953 UNITED STATES PA'IEN'I']y OFFICESfere,PQSJTIONINGIAPPAWUS Richard` W. May, Lexington, Mass., assignor`to National Company,` Inc., Malden, Mass., acor-Y porationA ofVVMassachusetts l This inventionrelatesto shaft positioning def vices;whereby, as a result of a controllingopera-l tion',v (for example Q theA manual positioning of4 a sWth arm or the depression of apush button) ashaftis brought 'tfoja'nd -stom'ed in` a s selected one ofIs'eve'rarl'pred,` t'ern1ine`dangular positions. The mevemet. of theshaft to itsj desiredjpqsition may; as .inthe apparatus hereiniuustrated and to bedescrib'ed injdetail, be effected by power. Aparticular and extensive i'leldofV use for` such a deviceliaintheviielfdof radiojwher'eintuning to a predetermined frequency is desired. In'such an application,l for example, the angular movenientV4 Voffftheshaft'might' effect a corresponding agngiilarl ladjustn'ient 'of facondenser.

` Iny thejconipletemechanism shown meansV are provided whereby inlresponse to a selective, manually. effected-ggvrnngcgritrl, the. Shaftis moved underfpovver throughalseries of predeterf n'iinedjpos'itiorisvand stoppedat theselected one, The mechanism. proifidles-l coordinatedimprove: mentsl forfpositio'ni'ng the` shaft by. variable amounts.'responsive to drivingv'movements of constant, predetermined stroke 'andalso -for varying asdesired,thepredetermined positions of rest withinthe angularrangfe of Inovernent"ofy the Shaft. Myinvention will be wellunderstood byreference ','to` the following` description ofthe'illustrativeV embodiment thereof. shown by way of examplel in theAaccompanying drawings. wherein:

' Fig. 1 is. a plan lview ofthe mechanism;

gigi 211s asectionnthieiine 'rv-+2` ofjFig. 1 Fig'. 3 isa fsecto'nblith" line, 3", -3' of. Ffgiy 2`; i'g.' lgis` 'al SCl'fon/OIr'tl'ie line4;-41`0fFg. 1'; 5gf5V isf'vs'tlfffh aflalglsale, on'the 1n5 5ofpigz4;Figs. 6 and 7 are fragmentary, enlarged sectionsy in the planes of lines6 -6 and 'I-"I of Fig. 5 respectively;

Figfisa wiring diagram; and

Figs. 9and 10`disc'lose vairnodification and are sectionssimilar to Fig.4, but simplified bythe omission of parts, showing in elevation a pairof actuatorsmin 'two different positions respectively, lReferringnow'toffFigfl, andv also toFvgs.: 2 and 5, the *mechanism shown isorganized in front and back frame plates Il). and' I2 respectively whichare spaced by pillarsv I4, andupper and lower guide .plates I 'B and I8l(see Fig. 5)v hereinafter mreflly to be described. Journalled'tobearings r'i'g; 5i in'V thejpiatesis a `sriafmn to, be positioned. `Inmost applications this vmight be @wandered as. the primary DQSitOledShaft and S molol .VlIUld 391if/ Il.nsenl/ed'its by the; gefs 2. 22 and24, Fig. 1, to`a sec'ondarypositioned-shaft 26 which might itself be theshaft of the mecha: nism (for example a'. condenser) whichtris desied`to operate', orl might drive., suchl ashaft through further mechanical.connections; The range of movement` ofthe shaft.` 20 in thep'resentinstance. is through approximately 180321-11611 have hereshown. (seeFig.5) acrosspin 28 extending through the. shaft.l Aand cooperating with;stop: screws' 3 [Il to. limit. the. movement. of the. shaft.

` In the eiranple `of` the, invention s ho'wni the shaft 2B has vepositions of angular adjustmentV and is moved to these positions by vee011*- responding driving pinions 32', to permit the. angular adjustmentofthe pinio'ns 'relativelyto the shaft and thus" theinitialslectioriendisubse quent change if desired. c'iftherestrpositions 'of the" shaft. These pinions `32.are 'not in'them'- selvesl'connectedto the shaft, butit'thereonY with slight frictiona'l.engagement. not effective to transmit considerable' load. This permits.their rotative' adjustment' about. the sliaft' 2D. and meanshereinafter'to be "described providesjfr locking the pinio'ns in fixedposition 'ontheshaft For the' present. it'willbe convenient tof'cnsiderthe p'nios as fixed 'to the shaft. Meshing with each 'of Athe pinions32at.opposite sides thereof, are upper and lower loose racks '34. HereinwhereA the range of movement of; the shaft is substantially the lngtlof'these racks'is desirably onlyslightly greater than 'the pitch"circumferen'ce of the pinions. Referring now 'to 4', when the'shaft2U'i`s positi'onedat.`a"se` lected'positi'on the corresponding pinion"32; by means of which it was turnedfto that position is cnteredfo'n thelracks`34.""1l'i`s rmay"lc`ie"`co"n` sidered theneutr'al "position of.the parts. 'Iffthe racks were nt restraine'dand'the sl'aft'ZUfwereturned "clockwise viewing'Fig. 4, the 'upper rack would move 'to the"right and the lower rack"`t`o the left. `If' it were movedounte'rclockwise 'the upper rack" would 'move tothe 'leftf'and the lowertothe right. 'With oneA set 'of raclsin the centered "position of Fig.'4"th`e' /otliersf may" beinr any positi'ori're1'ativet their'iiininsendif trie'fsh t is'freitlre movernetbf' araclfr" rnc W relativelydisplaced toward the tendiente 'site upper" rack' which is in' "Med,'t'o th V'le the ljen'trel"position, clokwi'se if U5 l.' xg'x'.' "il r"I thf` preceding paragraph I have referred to the .pinionasfceterdo"theraclgs'i "This" is true o'ftheejo t'riictin'as illustrated inthel'cofstruction the parts would be so centered or substantially so. In asense, however, such centering is not necessary, and I shall return tothis later after further description will make a fuller discussionpossible. I shall however throughout the specification use thislanguage, believing that it will promote ready understanding of theoperation, but it must be understood in the light of the discussionreferred to and which will follow.

To move the shaft to its selected positions means are provided formoving the racks of the corresponding pinions from such uncenteredpositions to the centered position. This is eiiected herein by slidingactuators A of fixed stroke. I have used the letter A instead of areference numeral to designate these actuators since they are composedof two parts, but it will be convenient to consider them as one tounderstand their general rule of action, and for such consideration asingle identifying designation is convenient.

I shall however at this place describe the two part construction ofthese actuators A. This description might be considered parenthetical inthis place, and the present paragraph and the next might be skipped if aquick outline of the operation is desired, and returned to later. Eachactuator A comprises two fiat plates or slides 36 and 38 the edges ofwhich are received in relatively deep grooves in plates i6 and I8 at oneside of the racks 34 which the actuator moves. The plates have centralopenings to permit the passage of the shaft and to permit thelongitudinal movement of the actuator relative thereto. The plate 3B,which is at the right in Fig. 5 and at the rear in Fig. 4, has an ear 49cooperating with the right-hand end of the upper guide plate I6 viewingFig. l (left-hand end, Fig. 4). See the three lower and the upperactuators in Fig. 1. These ears limit theV movement of the plates to theleft in that i-lgure, the plates being drawn to this extreme left-handposition by light springs 42. Dsplacing force is exerted on the oppositeend of the plate 34 to move it to the position of the actuator secondfrom the top in Fig. 1, this being effected by a cam 52 acting thereonas later described.

The plate 38 which lies at the left in Fig. 5 or toward the rear in Fig.4, rests against plate 36.

The plate 38 has lugs 44 entering relatively long notches 46 on theedges of plate 38. Relatively strong springs 41 tend to position theparts with the lug 44 at the right-hand ends of notches 4S viewing Fig.4. into the position shown by the `parts 44 and 46 appearing at theright of the gure and forming parts of an actuator at the rear. If themovement of plate 38 toward the left is arrested, as hereinafterexplained, the plate 36 under the action of the cam may continue to moveto the left against the force of the springs so that the parts 44 and 46come to the position shown more to the left of the figure as parts ofthe actuator at the front. The plate 38 has lugs 48 projecting laterallytherefrom across the paths of the racks 34 which are adjacent thereto.

For the moment we may consider the actuators A as unitary slidesnormally drawn to the right, Viewing Fig. 4, by the springs `42 andhaving lugs 48 extending across the paths of the adjacent racks 34. Whenthese slides are in such normal position as shown by those at the rearin Fig 4, the lugs 48 are at least as far to the right as the racks canbe moved by their pinion. If` the ,actuator is now given a slidingstroke of predetermined length toward the left, it picks up whicheverrack is extended toward it and returns the two to the centered positionshown in full lines in Fig. 1. If the upper rack were the one extendedtoward the right the pinion would be turned counterclockwise. If thelower were the one so extended the pinion would be turned clockwise. Theangular measure of the movement in either instance depends upon theposition of the rack when the movement of the actuator commences.

I now come, as mentioned previously, to a discussion of the statementthat in the position of Fig. 4 the pinion is centered on the racks. Forcompactness the length of the racks will correspond closely to thecircumference of the pinion with an additional tooth or so to preservethe engagement at the extremes of movement. It is clear however that wemight add, although quite uselessly, an additional length at thelefthand enclin Fig. 4 where nothing opposes the ends of the racks, andalso, quite uselessly, these additions might be of unequal amount. Also,we might add to the right-hand ends of the racks provided the drivinglugs 48 were moved so that they would be at a corresponding distancefurther to the right when moved to their extreme left-hand limit underthe influence of the cam, and in fact additions to the right-hand endsof the rack shown might be unequal in amount if the lugs 48 werecorrespondingly relatively di'splaced.

If the additions referred to were toothed, .they would in a descriptivesense be parts of the racks. However it will be apparent that theseteeth would not mesh with those of the pinion to drive the same or bedriven thereby. Hence the portions which functionally constitute rackswould be centered relative to the pinion when the parts were in theso-called neutral position illustrated by Fig. 4. Reference herein tothe racks as centered will therefore be understood to refer to thatportion of a physical structure which functions as a rack.

In the example of the invention shown, the actuators are driven from apower shaft 50 which, if it rotated continuously would simply move theactuators and the shaft and bring the shaft successively to its seriesof selected positions in regular recurrent order. The successivemovements of the shaft might vary in angular amount and in angulardirection. By means of a suitable interrupting device, however, thecycle is interrupted when a selected actuator has moved the racks driventhereby to centered position and the shaft is thereby brought to andheldin a selected predetermined position.

The shaft 5i) is herein a cam shaft having ranged around its periphery aseries of angularly displaced intermittent cams or wipers 52, oneopposing each of the actuators. Each cam has a nose 54 which moves intoengagement with the vertical end surface of the actuator plate 36 aswill be apparent by considering the actuators which appear at the rearin Fig. 4. As the shaft turns counterclockwise viewing that gure, thecam will urge the slider to the left as it wipes downwardly yalong thissurface. Following the nose portion 54 of the cam is a circular portion5S concentric with the axis of rotation which moves into engagement witha corresponding circular surface 5 8 at the lower end of the verticalend surface of the actuator which has just been referred to, as shown bythe actuator in front in Fig. 4. The stroke of the actuator toward the 1'eft'.1in..` that'nguref is.r thus f.; completed-..;v anda it remains-stationa1y.fwhile:the cam. revolves'- for a short'distance;Thisvprovides-'a period :wherein the shaft may. be. stopped .if thisparticular cam, actuator andv pinion. correspond to the desiredposition4 of the shaft. If not, the cam rides clear, releasingtheactuator and" thesnext .cam;operates the.1 next .actuator and. so. on.

Referring nowto- Figs. liand 3; theicam-.shaft 50i. is herein driven:from an electric :motor Itill, which maybe ofthe shaded. pole type,through reducinggearing 52 as-seen in Fig. 5 and afspring.-pressed'plungerx may bear.; against .theside of one-of the gears with a;force adjustable :..bymeans off'a.- screw: 65:1. The-motor lthussruns.against `--a constant brake,L Which has* beenA found a,v greatladyantagefin the `operation' of thegparts.

Ishavenotattempted to show `the. electricgfwiringin.:thefrealisticFigures 1-72 The operation of'the mechanism vfrom..theimotor will'be understood from: thev Wiring diagram, Fig. 8; Themechanism iszthere` shown as controlled by: a. suit.- able selectiveswitchv diagrammed as a: b'ank1of push buttonszl; 2, 3,. d, 5,' one Vforeachposition of the shaft and controlling parallel circuits forenergizing the motor. The motor drives. an interrupter switchhereembodying rotating conductive platesonthe camy shaft; a frontplate E8an'darrearfplate l 8, with which' -cooperate brushes unnecessaryftoidentify. byV a reference numeral. Five'brushes; each inrseriesy withone ofthe push buttons; equall'yfspaced.aboutlthe motor shaft makeconta-ctwwith theplate 1i). Thisrplatefhas a notch 'I2 and when one ofthe brushesenters the` notch' theA motor: energizing circuit is Abrokenatthis.-point; There is nothing essentiallynovel about thisswitch assuch.

InfFig; S'the shaft-isfstopped a-.tlposition 3, correspondingtopushbuttonSf. Supposenow we Wish to move. toA station 2. Push button 2is depressed, energizing the-motor.A Nomea-ns are here illustrated' forkeep-ing the push button in, itlbeing. assumed that the-*operator-Wi'llkeep it depressedA manually until thel new station. is rea-ched. I haveherein shown signal lights 'M'. associated with each push buttoncircuit, so that a lampV lights When push. button 2 is: depressed andtheY operator will keep-the button down until the circuit isbroken. Whentheinotor stops the light. will go out, and`- heWill be informed thatthefnewposition of the-shafthas-been reached. The motorz being.energized through closed push buttonz, plate Yiii-.Will beginY toturncounterclock- Wiseviewing -thegura the-shaftZ i! will'bemoved throughposition 4, position 5 `and position- 1', and thenv the-notch 7.2 willcome. tothe-brush in the circuit. of-"push button Efand the -motor Willstop', with'` the correspondingcam 52 resting with its circular surface5dA engagingv surface 555" of! the corresponding actuator and the`corresponding racks 323.1 centered onv their pinion 32v asV seenin Fig.4l.

To permit angular adjustment of thepinions 32 and shaft 3l! so that'the'latter will be. in'. desired angularposition whenl an given pinionis turned byfthe action of its cam to-theVY neutrali rack-centereclposition of- Fig. 4j and to permit alteration ofV these positions;releasable means is provided for connecting the pinions, which asalready mentioned inand of themselveslare free on the shaft, in*-driving relation to the same. Herein sleevesare alternated With thepinions and the sleeves 80 are keyed to the shaftv with freedom oflongitudinal movement therealong by means -ofballs'32 at diametricallyoppositev points., which 75 balls: are receiyedf in vfshapedways .841agdalgofmeenam and v.shape i;ggrgeve -s irithesleeves. (see Figs;` 5,' 6vand 7).. Whenwthe;:assemhlageis axially clamped Y. the gearsand j shaftmove= tog semer.v Ifrthe clampi-nsvpressure..isfrelfxedthe shaft may: ben rotated relatively-.Jl to"r am.r pinion which is-he-ld fixed-as is,thefpinion showninl ig-, 4.; by the racks which restgagainSt;,thedugs48of. lactuator A. in turn held by acam, ,52.--

Suppose. we. wish to Vadjust `rthepos ition 4offthe shaft vso that.actuation by a-given3pinion-- gives it the requiredangular adjustment-lThe pinion 3 2 is:.brought to rest with; its correspondingactu atorandcam'Z inthe positions; o fFig;` 4.;4- The axial clamping pressure ofthe pinionsdisgrelweased; The particular v pinion; question; turn.

being. lockedY by. one; 0.1'.- the;v other; ofithe racksabutting.thelugs 48.: The; shaftym turned' within thepinionasfby-mea uj likehandleor knobv thereou (Fig 1;),;to;a;n ew position. Thus, if we areconcerned Withgaradio apparatus. weV might .-tune. in a` sign a .ll on-.afnew frequency. After; thisY is donethe pinions are clamped againstthesleeves'ionce againand therefore the return at any later time of thispars ticular pinion to the same position will `move the shaft to the newposition of adjustment;l During this readjustment vthe other'racksmesh-.ing with the. other: pinions are-unrestrained.; FrQtiOn-:Ssuii'cient .to cause these; pinionsto :turri with the shaft and'to drivethe ,racksiso thattheel position of these other pinions to the Shitremains unaltered.` Friction between the-.latter pinionsand theinterposedv sleevesz .keyedtcr the shaft, Which'. friction isv duetothe; pressure of spring washers 92: as hereinafter explained.. issuiiicient.'

The `parts are.v clamped (see Fig; 5)?, withgat; tendantA compression ofthe spr-inge Washers-.1 9.2., byian adjusting nut' 94 threadedl ontothe. end of the shaft'I 2G and turnedby. knob 96v (Fig. 1i". ThelWashers bear -against the outerrace- 981ofa ball thrust bearing; theinnerrace.. i001 cfg-which is carried by a sleeve. |62, which also.:carries the. inner -race of the. forward journal bearing. A member |04at the inner'end' off this. sleeve presses against the forward.. end ofthe stack of sleeves` 83. and pinions- 32 which stack is supported attherear bya sleeve |06 bearing against a shoulder lon the-shaft.-'Iheentiremecha-` nism turns freely With theshaft duringnormal use.Thereisno tendency--to'disturb the-angular relation of the parts whenthetnutflllis turned; Any-drag of' thefnut-is absorbed by: the-.freerace 98. When the. nuty is. backedoff' the washersas explainedabovestill maintain-.suiiicientfpressureA onthe stack of4 pinions-andWashers: so that, with the exception of' thepnefpositioned bythecam,theyvvilll turnv as aunit Withl the shaftLwhen the latter. is turnedWithin the. one .so held.

The actuators A, as; already described, comprise two platesV and 33connectedbyfsprings 46; The former drives the latterfthroug'hthesprings. Thus, referring: toA Fig. 4, when; the plate 36. was moved: totheL left'. to.y the position shown, springs-'6371: anchored to. theplate atttheir left-hand endsacted astension connections to draw. plate38 also to the left.. If the springs did. notyieldor what amounts to thesamething if the plates 36 and 38 were in one piece i-tAW/ould betheoretically possible to. have. an. apparatus operating ashereinbeforeI described. However for practical reasons aI lost motion,isl prouided between. the: cam followerfplate 3,8 andhemacks 31k inthecentered position. of the latter.. when.

both racks abut lugs 48 on plate 35 and the driven pinion is in itsdesired position, plate 35 can no longer move to the left. The cam is sodesigned that it may move plate 38 a further short distance, extendingsprings 41 and moving lug 44 to the left in slot 45. Hence minorinaccuracies of construction, looseness of the parts, and the effects ofwear are taken care of. Also, when the shaft is position with one of thepinions locked as indicated in Fig. a slight manual movement may beeffected by means of the knob Sil useful in checking the accuracy of theadjustment. The parts return automatically under the action of theSprings after such manual movement.

' As best seen in Fig. 4 the plate 3S may be provided with slightembossed projections lll which extend over the ends of the racks 34 andprevent their displacement from the grooves which receive them when theracks are moved to extreme positions.

I also show (see Figs. 1, 2 and 4) a leaf spring i2 secured toV bottomguide plate I8, having a number of projecting tongues H4 which extendover the edge of this plate and are adapted to be engaged by the edge ofplate 38 of the actuator when the actuator is moved from the in positionto the out position of Figs. 2 and 4. The parts as they move to and whenthey are in the position shown in Fig. 4 are thus firmly held and thereis no undesirable looseness.

InFigs. 9 and l0 I show a modification of the actuator and the drivingmeans therefor which in a sense may be considered as providing for aninversion of the movements of those parts in the other gures. In themodification of Figs. l to 7 `iust described, the actuators are normallydrawn to neutral or idle position toward the right in Fig. 4 by springs42. The cams 52 push them to the left and the centered position of theparts corresponds (subject to what has been said concerning the actionof springs 41) to the high point or nose of the cam. In the modificationas illustrated by the nearer actuator seen in Fig. 1G on the contrarythe actuators are held in the idle position against a spring by theaction of a circular portion of a cam which has an eccentric portionextending inwardly to a low point and the actuator is by this eccentricportion released to the action of the spring and moved thereby to anextreme position wherein the racks are centered as seen in Fig. 9.

Referring to the figures the shaft 25, pinions 32 and racks 34 are likethose in Figs. l to 1 and are similarly positioned and arranged forcooperation. The actuator comprises a single plate |35 Similar to plate35 and similarly mounted, and it has lugs |44 for engaging the ends ofthe racks 34 but these are at the end of the plate which is at theopposite side of shaft 25 from cam shaft 55. Springs 42 normally tend todraw the actuators |35 to the right in the case of the nearer actuatorin Fig. 9 into an extreme position wherein lugs |44 engage the ends ofthe racks and move them to centered position in the sense alreadyexplained. The plates |35 have followers |31 projecting therefromcooperating with cams |52 on the cam shaft 5G, one for each actuator.

Each cam |52 is a disc circular for the greater portion of itscircumference, but having an eccentric portion |53 defining a sharp dropto a low point |55 at which the cam surface may be circular for a shortdistance and from which it continues as a rise |51 to the exteriorcircular surface first mentioned. The cam has the general form of acircular disc with a notch or depression of limited circumferentialextent defining a low point. These depressions are angularly offset inthe several cams of the system.

As the cam shaft turns the follower |31 of one of the actuators ridingalong on the outer circumferential edge of its cam |52 will come to theeccentric portion |53 which will release the actuator to its spring |42which quickly draws it to the right to the position of Fig. 9 as seen atthe front of the figure. For a short period the follower is oppositesurface |55. Then the surface |51 returns the follower to the circularperiphery of its cam tothe position shown in the front of Fig. 10. Thedepressions in the cams occupy separate segments of the circular areaabout cam shaft 55 so the several actuators are reciprocated inrecurrent sequence. The motor is stopped at a selected position as inthe other modification when the pertinent actuator has its follower atlow point |55 of its cam.

In the extreme position of the plate wherein its movement is stopped bythe simultaneous engagement of lugs |44 with both racks 34 a clearanceis provided between the follower |31 and the low point |55 of the camand between the lug 45 to which spring |42 is anchored and theplate I5.The actuator thus is always spring driven to the desired extremeposition corresponding to the centered position of the racks. Noauxiliary plate similar to 38 in the other modification is required.

I am aware that the invention may be embodied in other specific formswithout departing from the spirit or essential attributes thereof, and Itherefore desire the present embodiment to be considered in all respectsas illustrative and not restrictive, as is in fact clear in severalmatters from the description itself. Reference is to be had to theappended claims to indicate those principles of the invention exempliedby` the particular embodiment described and which I desire to secure byLetters Patent.

I claim:

l. Shaft positioning apparatus comprising a shaft having a series ofgears thereon, racks meshing with each gear at opposite sides thereof, asliding rack actuator for each gear, a cam shaft having a cam for eachactuator, each cam ,being shaped to provide for movement of the actuatorto an extreme position during which movement it drives the racks and forits return from such position to an idle position, both in a limitedangular movement of the cam shaft, the cams being angularly offset toprovide for such movement of the actuators in regular recurrent order oncomplete rotations of their shaft, a motor driving the cam shaft, aplurality of manually controlled switches corresponding to the cams eachcontrolling a circuit for energizing the motor and an interrupter switchrotating in tuned relation to the motor to break such circuits when thecorresponding cam has caused movement of its actuator to its extremeposition.

2. Shaft positioning apparatus comprising a shaft, a series of driverscarried thereby with provision for selective angular positioning of thesame thereon, motion-transmitting devices connected to said drivers tomove the latter and to be moved thereby in relatively oppositedirections, a series of actuators apposing the devices of the severaldrivers, a cam shaft having cams with angularly offset portions whichmovel when 59 the shaft revolvesgginvregularfrecurrent order intoeiective, apposition Y,to said actuators to provide for their movementinto engagement with aV motion-transmitting device which' hasbeen movedtoward su'chf camf-and-fforthereturn-of the two motion-,transmittingdevices to neutral position,

:azzmotorrdriving the cam shaft. and meansfor energizingfthe samecomprisinga selector switch '.and a cooperating interrupter switchdrivenfrom the' motorfto cause rotation ofi-the motos. and

stopping of the sameg-whenza4 selected camA has acted.

1.3. Shaft;positioning apparatus comprising `a shaft.a` series ofdrivers carried thereby .with provision for relative angular adjustment;actuators operatively related to the, vdri-vers respectively Vfor;movingthe latter,va cam shafthaving aseries iof camsione for each ofthe'actuatorsthefcams being, shaped to providei for rmovement; offfthelatter to an extreme position and thereby for movement of the driversyand for the return of the actuators to idle positions in regularlyrecurrent order as the cam shaft revolves, a nonreversing motor drivingthe cam shaft and means for energizing the saine comprising a selectorswitch mechanism controlling circuits corresponding in number to thenumber of actuators and a cooperating interrupter switch turning in timerelation to the cam shaft to break said circuits respectively when thecorresponding cam has caused movement of the actuator to its extremeposition.

4. Shaft positioning apparatus comprising a shaft, a series of driverscarried thereby, actuators operatively related to the driversrespectively for moving the latter, a cam shaft having cams for eachactuator for successively moving the same as the shaft revolves, eachcam having a nose portion and the actuator a portion engaged thereby toprovide for movement of the actuator and the cam and actuator alsohaving circular portions of limited extent which engage subsequent tosuch movement to maintain temporarily the actuator in the position towhich it has been moved during a limited continued motion of the cam, amotor driving the cam shaft and means for energizing the same comprisinga selector switch yand a cooperating interrupter switch driven from themotor effective to break the motor circuit during the period ofengagement of said circular portions.

5. Shaft positioning apparatus comprising a shaft, a series of driverscarried thereby, actuators operatively related to the driversrespectively for moving the latter, a cam shaft having cams for eachactuator for successively moving the same as the shaft revolves, eachcam having a nose portion and the actuator a portion engaged thereby toprovide for movement of the actuator, a motor driving the cam shaft,means for energizing the motor comprising a selector switch and acooperating interrupter switch driven from the motor effective to breakthe motor circuit when the cam nose portion has completed its action onits related actuator and a mechanical brake constantly opposing therotation of tne motor.

6. Shaft positioning apparatus comprising a shaft, a series of driverscarried thereby, actuators operatively related to the driversrespectively for moving the latter, a cam shaft having cams, one foreach actuator, for successively moving the actuators as the shaftrevolves, each cam having an eccentric portion and the actuator afollower cooperating with the same, the eccenviris,portions o-f,the.,sev.era1.Qamsbeinsrailged in L.ansulalli. spaced positions a out theshaf a motor driving thelcam shaitameans-for. ingthemotor.comprisingaselewtor. switch.. da cooperating linteHunt,er.s,.witchdriyengfromgvthe motor, effective,Y to break the, 111o tpr circuitl when,theeccentric ,portion `of Ia ,camy Yhas onipletedits lactionon .itsArelated .actuator and a,rnechanical ybrake constant1v-opppsnetherqtaiignf .the motor.

7. shaft positioning apparatus .as Claim a4 Whereimamechanic-a1.brake-tombeaux'. QRPQQS rotation ,of` themotor. v`

8. .shaft positioning apparatus :omnrisinga lshaft` having a, series`offdriversthereon, re' procating actuators `operative.1v related tmseiddrivers respectively, springs 'for returning the .actuators tomaninitial position nand means for gnoving, eacnactuator ,comprising anintermittent cam,ariannally. controled, meansifoni ing the ,cam pastthe, end of ,angactpatoh thepain .havina-fatnosa portion and. the,asiuatorgha ,ne a1 r portion engagedA thereby...t0, provide;fonmeimentgoft 'thegaotuator against the-^force of" the spring from suchinitial position, the cam and actuator having circular portions oflimited extent which engage subsequently to such movement, and means forreleasing and for effecting the circumferential driving connection ofthe drivers t0 the shaft whereby the angular position of the shaft tothe driver may be altered while said circular portions are inengagement.

9. Shaft positioning apparatus comprising a shaft having `a series ofpinions thereon, loose racks meshing with each pinion at opposite sidesof the latter, a reciprocating .actuator for each pinion havingabutments at one side of the shaft for engaging the ends of the racks,means for normally positioning the actuator with Wsaid abutments atleast as far from the shaft as the extreme position of the end of a rackmoved toward that side and means for moving any selected actuator to andretaining it in a position wherein the racks are centered relative tothe pinion, the actuator comprising two parts, one engaging the racksand the other connected to the rst through a yielding driving connectionpermitting continued movement of the said other part after the first hasengaged the racks.

1i). Shaft positioning apparatus comprising -a shaft having a series ofpinions thereon, loose racks meshing with each pinion at opposite sidesof the latter, a reciprocating actuator for each pinion having abutmentsat one side of the shaft for engaging the ends of the racks, means fornorm-ally positioning the actuator with said abutments at least as farfrom the shaft as the extreme lposition of the end of a rack movedtoward that side, a cam shaft having a series of intermittent camsranged about its circumference and apposing the actuators respectivelyfor engaging the actuators respectively and moving them to positionswherein the racks are centered relatively to the pinion whereby rotationof the shaft to a selected angular position will move the racks of apredetermined pinion to such centered position with resultant angularpositioning of the pinion shaft.

11. An apparatus as defined in claim 10 wherein the actuator comprisestwo parts, one engaging the racks and the other being a cam followerconnected to the rst through a yielding driving connection permittingcontinued movement of the said other part after the first has engagedthe racks.

12. Shaft positioning apparatus comprising a shaft having a series ofpinions thereon, loose racks meshing with each pinion at opposite sidesof the latter, a reciprocating actuator for each pinion having abutmentsat one side of the shaft for engaging the ends of the racks, means fornormally positioning the actuator with said abutments at least as farfrom the shaft as the extreme position of the end of a rack moved towardthat side, a cam shaft having a series of cams one for each actuator forsuccessively moving the actuators as the shaft revolves each cam havingan eccentric portion and the actuator a follower cooperating therewith,the eccentric portions of the several cams being ranged in angularlyspaced positions around the shaft, the cooperation of said eccentricportions and followers providing for movement of the actuators topositions wherein the racks are centered relatively to the pinionwhereby rotation of the shaft to a selected angular position will movethe racks of a predetermined pinion to such centered position withresultant angular positioning of the pinion shaft.

RICHARD W. MAY.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,851,571 Doman Mar. 29. 19321,868,385 Greenwood July 19, 1932 2,197,155 Nardone Apr. 16, 19402,277,134 Nelson Mar. 24, 1942 2,296,060 Schwarz et al Sept. 15, 19422,305,326 Swallow Dec. 15, 1942 2,384,561 Muiett Sept. 11, 19452,410,091 Lynch Oct, 29, 1946 2,444,840 May July 6, 1948 2,480,373Leishman Aug. 30, 1949 2,488,866 Illmer Nov. 22, 1949 2,550,015 WaldronJuly 10, 1951 2,571,303 Spiller et al. Oct. 16, 1951

